Catalytic dewaxing process

ABSTRACT

The invention relates to a process for the catalytic dewaxing of a hydrocarbon feed containing waxy molecules by contacting the hydrocarbon feed under catalytic dewaxing conditions with a catalyst composition having metallosilicate crystallites, a binder and a hydrogenation component, wherein the weight ratio of the metallosilicate crystallites and the binder is between 5:95 and 35:65. The invention also relates to a catalyst composition having at least a low acidity refractory oxide binder, which binder is essentially free of aluminum, metallosilicate crystallites and a hydrogenation component, wherein the weight ratio of the metallosilicate crystallites and the binder is between 5:95 and 35:65.

FIELD OF THE INVENTION

The invention relates to a process for the catalytic dewaxing of ahydrocarbon feed comprising waxy molecules by contacting the hydrocarbonfeed under catalytic dewaxing conditions with a catalyst compositioncomprising metallosilicate crystallites, a binder and a hydrogenationcomponent. With the term comprising used in this specification is meantcomprising at least meaning that also other components may be presentin, for example the catalyst composition or hydrocarbon feed.

BACKGROUND OF THE INVENTION

Such a process is described in EP-A-185448. This patent publicationdiscloses a process for the manufacture of lubricating oils in which ahydrocarbon feedstock is subjected to catalytic dewaxing in the presenceof a catalyst composition consisting of ZSM-22, an alumina binder andplatinum. The catalyst was prepared by impregnating an extrudateconsisting of 65 wt % ZSM-22 and 35 wt % alumina resulting in a catalystcontaining 0.57 wt % of platinum.

There is a continuous effort in the field of catalytic dewaxing ofimproving the yield and the viscosity index (VI) of the lubricatingobtained by said process. Furthermore efforts are made to provide acatalytic dewaxing process which can compete with solvent dewaxingprocesses in respect of for example oil yield and viscosity index at thesame pour point specification. Solvent dewaxing is a difficult tooperate semi-continuous process. Being able to replace a solventextraction process by a catalytic dewaxing process is thereforedesirable.

SUMMARY OF THE INVENTION

The object of the invention has been achieved when the weight ratio ofthe metallosilicate crystallites and the binder is between 5:95 and35:65.

It has been found that with the present process a high yield of base oilproduct can be obtained at the same weight hourly space velocity. Thisimplies that with a lower amount of metallosilicate crystallites moredewaxing selectivity is achieved. Furthermore it results in that thecatalyst employed in the process according to the invention is cheaperthan the prior art catalysts because less of the relatively moreexpensive metallosilicate crystallites is used in the catalystcomposition. An additional advantage is that the gas make is lower withthe present process.

WO-A-9617902 describes a catalyst composition for the catalytic dewaxingcomprising of a aluminosilicate zeolite material and a binder in amountsfrom 80:20 to 20:80 by weight and typically from 80:20 to 50:50zeolite:binder.

EP-A-304251 describes a catalytic dewaxing process in which preferably acatalyst composition is used without a binder. The catalyst used in theexperiments is a nickel on ZSM-5 catalyst without a binder.

DETAILED DESCRIPTION OF THE INVENTION

By catalytic dewaxing is here meant a process for decreasing the pourpoint of lubricating base oil products by selectively converting thecomponents of the oil feed which impart a high pour point to productswhich do not impart a high pour point. Products which impart a high pourpoint are compounds having a high melting point. These compounds arereferred to as waxes. Wax compounds include for example high temperaturemelting normal paraffins, iso-paraffins and mono-ringed compounds. Thepour point is preferably reduced by at least 10° C. and more preferablyby at least 20° C. The hydrocarbon oils to be used as feed in theprocess according to the present invention will thus contain waxymolecules which impart an undesirable high pour point. Small amounts ofthese compounds can strongly influence the pour point. The feed willsuitably contain between about 1% and up to 100% of these waxycompounds.

Suitable hydrocarbon oil feeds to be employed in the process accordingto the present invention are mixtures of high-boiling hydrocarbons, suchas, for instance, heavy oil fractions. It has been found particularlysuitable to use vacuum distillate fractions derived from an atmosphericresidue, i.e. distillate fractions obtained by vacuum distillation of aresidual fraction which in return is obtained by atmosphericdistillation of a crude oil, as the feed. The boiling range of such avacuum distillate fraction is usually between 300 and 620° C., suitablybetween 350 and 580° C. However, deasphalted residual oil fractions,including both deasphalted atmospheric residues and deasphalted vacuumresidues, may also be applied. If the vacuum distillate fractionscontain substantial amounts of sulphur- and nitrogen-containingcontaminants, for example, having sulphur levels up to 3% by weight andnitrogen levels up to 1% by weight, it may be advantageous to treat thisfeedstock to a hydrodesulphurisation and hydrodenitrogenation step priorto the catalytic dewaxing process according to the present invention.

Examples of feeds having relatively high amounts of waxy compounds aresynthetic waxy raffinates (Fischer-Tropsch waxy raffinates),hydrocracker bottom fractions (hydrowax), i.e. those fractions having aneffective cutpoint of at least 320° C., preferably at least 360° C. andslack waxes obtained from the dewaxing of hydro-processed or solventrefined waxy distillates. These feeds have a wax content of at least 50%by weight, preferably at least 80% by weight and more preferably atleast 90% by weight. These feeds are used to prepare lubricating baseoils having viscosity indices (VI) above 120 and particularly above 135.

Prior to the catalytic dewaxing process according to the invention thevacuum distillate fraction or any other sulphur or nitrogen containingfeedstock is preferably treated to a hydrotreating step in order toreduce the concentration of sulphur and/or nitrogen in the feed. Thehydrotreating step preferably involves contacting the feed with hydrogenin the presence of a suitable catalyst. Such catalysts are known in theart and in principle any hydrotreating catalyst known to be active inthe hydrodesulphurisation and hydrodenitrogenation of the relevanthydrocarbon feeds may be used. Suitable catalysts, then, include thosecatalysts comprising as the non-noble Group VIII metal component one ormore of nickel (Ni) and cobalt (Co) in an amount of from 1 to 25 percentby weight (%wt), preferably 2 to 15% wt, calculated as element relativeto total weight of catalyst and as the Group VIB metal component one ormore of molybdenum (Mo) and tungsten (W) in an amount of from 5 to 30%wt, preferably 10 to 25% wt, calculated as element relative to totalweight of catalyst. These metal components may be present in elemental,oxidic and/or sulphidic form and are supported on a refractory oxidecarrier. The refractory oxide support of the first stage catalyst may beany inorganic oxide, alumino-silicate or combination of these,optionally in combination with an inert binder material. Examples ofsuitable refractory oxides include inorganic oxides, such as alumina,silica, titania, zirconia, boria, silica-alumina, fluorided alumina,fluorided silica-alumina and mixtures of two or more of these. In apreferred embodiment an acidic carrier such as alumina, silica-aluminaor fluorided alumina is used as the refractory oxide carrier. Therefractory oxide support may also be an aluminosilicate. Both syntheticand naturally occurring aluminosilicates may be used. Examples arenatural or dealuminated zeolite beta, faujasite and zeolite Y. From aselectivity point of view it is preferred to use the dealuminated formof these zeolites. A preferred aluminosilicate to be applied isalumina-bound, at least partially dealuminated, zeolite Y.

Catalytic dewaxing conditions are known in the art and typically involveoperating temperatures in the range of from 200 to 500° C., suitablyfrom 250 to 400° C., hydrogen pressures in the range of from 10 to 200bar, suitably from 15 to 100 bar, more suitably from 15 to 65 bar,weight hourly space velocities (WHSV) in the range of from 0.1 to 10 kgof oil per liter of catalyst per hour (kg/l/hr), suitably from 0.2 to 5kg/l/hr, more suitably from 0.5 to 3 kg/l/hr and hydrogen to oil ratiosin the range of from 100 to 2,000 liters of hydrogen per liter of oil.

The weight ratio of the metallosilicate crystallites and the binder isbetween 5:95 and 35:65. Preferably the weight ratio is 10:90 and above.The upper ratio is preferably lower than 30:70. It has been found that alower ratio is beneficial for achieving the advantages of the presentinvention. However when lowering this ratio a higher operatingtemperature is required to achieve a comparable pour point reduction.Therefore a ratio of 5:95 is the practical lower range of themetallosilicate crystallites to binder weight ratio, because at lowerratios the required operating temperatures will be too high forpractical applications.

The binder can be a synthetic or naturally occurring (inorganic)substance, for example clay, silica and/or metal oxides. Naturaloccurring clays are for example of the montmorillonite and kaolinfamilies. The binder is preferably a porous binder material, for examplea refractory oxide of which examples are: alumina, silica-alumina,silica-magnesia, silica-zirconia, silica-thoria, silica-beryllia,silica-titania as well as ternary compositions for examplesilica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesiaand silica-magnesia-zirconia. More preferably a low acidity refractoryoxide binder material which is essentially free of alumina is used.Examples of these binder materials are as silica, zirconia, titaniumdioxide, germanium dioxide, boria and mixtures of two or more of theseof which examples are listed above. The most preferred binder is silica.

The hydrogenation component suitably comprises at least one Group VIBmetal component and/or at least one Group VIII metal component. GroupVIB metal components include tungsten, molybdenum and/or chromium assulphide, oxide and/or in elemental form. If present, a Group VIB metalcomponent is suitably present in an amount of from 1 to 35% by weight,more suitably from 5 to 30% by weight, calculated as element and basedon total weight of support, i.e. modified molecular sieve plus binder.

More preferably only a Group VIII metal component is present as thecatalytically active hydrogenation component. Group VIII metalcomponents include those components based on both noble and non-noblemetals. Particularly suitable Group VIII metal components, accordingly,are palladium, platinum, nickel and/or cobalt in sulphidic, oxidicand/or elemental form. The total amount Group VIII metal will suitablynot exceed 10% by weight calculated as element and based on total weightof support, and preferably is in the range of from 0.1 to 5.0% byweight, more preferably from 0.2 to 3.0% by weight. If both platinum andpalladium are present, the weight ratio of platinum to palladium mayvary within wide limits, but suitably is in the range of from 0.05 to10, more suitably 0.1 to 5. Catalysts comprising palladium and/orplatinum as the hydrogenation component are preferred.

The metallosilicate crystallites have a crystalline microporousstructure and can generally be defined as being built up ofthree-dimensional frameworks of tetrahedral SiO₄ units and tetrahedral Munits or tetrahedral SiO₄ units and octahedral M units which units arecorner linked via oxygen atoms. Examples of possible metals for M areAl, Fe, B, Ga or Ti or combinations of these metals. Preferredmetallosilicate crystallites are aluminosilicate zeolite crystallitessuitably having pores with a diameter in the range of from 0.35 to 0.80nm. Preferred aluminosilicate zeolite crystallites include MFI-typezeolites having pores with diameters of 0.55 and 0.56 nm, such as ZSM-5and silicalite, offretite having pores with diameters of approximately0.68 nm and zeolites of the ferrierite group having pores with diameterof 0.54 nm, such as ZSM-35 and ferrierite. Another preferred class ofaluminosilicate zeolite crystallites include TON-type zeolites. Examplesof TON-type aluminosilicate zeolite crystallites are ZSM-22, Theta-1 andNu-10 as described in U.S. Pat. No. 5,336,478, EP-A-57049 andEP-A-65400. A further preferred class of aluminosilicate. zeolitecrystallites are of the MTW-type. Examples of molecular sievecrystallites having the MTW-type topology are ZSM-12, Nu-13,TEA-silicate, TPZ-3, TPZ-12, VS-12 and Theta-3 as for example describedin U.S. Pat. No. 3,832,449, EP-A-513118, EP-A-59059 and EP-A-162719. Anext preferred class of aluminosilicate zeolite crystallites are of theMTT-type. Examples of alumino-silicate zeolite crystallites having theMTT-type topology are ZSM-23, SSZ-32, ISI-4, KZ-1, EU-1, EU-4 and EU-13as for example described U.S. Pat. No. 4,076,842, U.S. Pat. No.4,619,820, EP-A-522196, EP-A-108486 and EP-A-42226.

More preferably the zeolite crystallites have a Constraint Index ofbetween 2 and 12. The Constraint Index is a measure of the extent towhich a zeolite provides control to molecules of varying sizes to itsinternal structure of the zeolite. Zeolites which provide a highlyrestricted access to and egress from its internal structure have a highvalue for the Constraint Index. On the other hand, zeolites whichprovide relatively free access to the internal zeolite structure have alow value for the Constraint Index, and usually pores of large size. Themethod by which Constraint Index is determined is described fully inU.S. Pat. No. 4,016,218, incorporated herein by reference for details ofthe method.

Constraint Index (CI) values for some typical materials are:

CI (At Test Temperature) ZSM-4 0.5 (316° C.) ZSM-5   6-8.3 (371-316° C.)ZSM-11   6-8.7 (371-316° C.) ZSM-12 2.3 (316° C.) ZSM-20 0.5 (371° C.)ZSM-22 7.3 (427° C.) ZSM-23 9.1 (427° C.) ZSM-34 50   (371° C.) ZSM-354.5 (454° C.) ZSM-38 2   (510° C.) ZSM-48 3.5 (538° C.) ZSM-50 2.1 (427°C.) TMA Offretite 3.7 (316° C.) TEA Mordenite 0.4 (316° C.)Clinoptilolite 3.4 (510° C.) Mordenite 0.5 (316° C.) REY 0.4 (316° C.)Amorphous Silica-Alumina 0.6 (538° C.) Dealuminized Y (Deal Y) 0.5 (510°C.) Erionite 38   (316° C.) Zeolite Beta 0.6-2   (316-399° C.)

The very nature of the Constraint Index and the recited technique bywhich it is determined, however, admit of the possibility that a givenzeolite can be tested under somewhat different conditions and therebyexhibit different Constraint Indices. Constraint Index seems to varysomewhat with severity of operation (conversion) and the presence orabsence of binders. Likewise, other variables, such as crystal size ofthe zeolite, the presence of occluded contaminants, etc., may affect theConstraint Index. Therefore, it will be appreciated that it may bepossible to so select test conditions, e.g., temperature, as toestablish more than one value for the Constraint Index of a particularzeolite. This explains the range of Constraint Indices for zeolites,such as ZSM-5, ZSM-11 and Zeolite Beta in the above Table.

When using the above described classes of alumino-silicate zeolitecrystallites, especially the zeolites of the MFI and MTW type, it hasbeen found to be advantageous to subject the catalyst to a dealuminationtreatment. Advantages of this treatment are a further increase of theyield of lubricating base oil, an improved stability of the catalystand/or an improved crush strenght of the final catalyst. Dealuminationresults in a reduction of the number of alumina moieties present in thezeolite and hence in a reduction of the mole percentage of alumina.

Dealumination treatment is preferably performed in that the surface ofthe zeolite crystallites is selectively dealuminated. Surfacedealumination results in a reduction of the number of surface acid sitesof the zeolite crystallites, whilst not affecting the internal structureof the zeolite crystallites. The extent of dealumination of the surfaceof the crystallites depends on the severity of the dealuminationtreatment. Suitably, the number of surface acid sites of the zeolite isreduced with at least 70%, preferably with at least 80% and even morepreferably with at least 90%. In a most preferred embodiment the numberof surface acid sites is reduced with essentially 100% by the selectivedealumination, thus leaving essentially no surface acid sites at all.

Dealumination can be attained by methods known in the art. Particularlyuseful methods are those, wherein the dealumination selectively occurs,or anyhow is claimed to occur selectively, at the surface of thecrystallites of the molecular sieve. Examples of dealumination processesare described in WO-A-9641849. Preferably dealumination is performed bya process in which the zeolite is contacted with an aqueous solution ofa fluorosilicate salt wherein the fluorosilicate salt is represented bythe formula:

(A)_(2/b)SiF₆

wherein ‘A’ is a metallic or non-metallic cation other than H+ havingthe valence ‘b’. Examples of cations ‘b’ are alkylammonium, NH₄ ⁺, Mg⁺⁺,Li⁺, Na⁺, K⁺, Ba⁺⁺, Cd⁺⁺, Cu⁺, Ca⁺⁺, Cs⁺, Fe⁺⁺, Co⁺⁺, Pb⁺⁺, Mn⁺⁺, Rb⁺,Ag⁺, Sr⁺⁺, Tl⁺, and Zn⁺⁺. Preferably ‘A’ is the ammonium cation. Thezeolite material may be contacted with the fluorosilicate salt in anamount of at least 0.0075 moles per 100 grams of the zeolite material.The pH is suitably between 3 and 7. An example of the above describeddealumination process also referred to as the AHS treatment, isdescribed in U.S. Pat. No. 5,157,191.

When zeolite crystallites are used which have been subjected to adealumination treatment the binder material is preferably a materialwhich does not introduce acidity into the modified zeolite crystallite.Such a binder material is preferably the above described low acidityrefractory oxide, which is essentially free of aluminium. It has beenfound that an increased mechanical strenght of the catalyst extrudate isobtained when prepared according to this sequence of steps.

The crystallite size of the zeolite may be as high as 100 micron.Preferably small crystallites are used in order to achieve an optimumcatalytic activity.

Preferably crystallites smaller than 10 micron and more preferablysmaller than 1 micron are used. The practical lower limit is suitably0.1 micron. It has been found that the combination of small sizecrystallites and a surface dealumination treatment, especially the AHStreatment, as described above results in more active catalyst whencompared to the same, but non-dealuminated, catalyst. Preferablecatalysts are used having a crystallite size of between 0.05 and 0.2 μmand which have been subjected to a dealumination treatment. Theinvention is also directed to the novel catalyst compositions havingsuch small size surface dealuminated zeolite crystallites and lowacidity binder materials and their use in hydrocarbon conversionprocesses, optionally also comprising a Group VIII or Group VIB metal ofwhich examples are mentioned above. Suitable processes are catalyticdewaxing, hydroisomerisation and hydrocracking.

A disadvantage of a catalyst composition having a low content ofmetallosilicate crystallites is that the crush strength is not alwayshigh enough to suit practical application. To overcome this problemapplicants have now found a preferred method of preparing such catalystshaving an improved crush strength as will be described below. The methodis especially suitable when using a low acidity refractory binder. Thismethod comprises the steps of:

(a) preparing an extrudable mass comprising a substantially homogenousmixture of metallosilicate crystallites, water, a source of the lowacidity refractory oxide binder present as a mixture of a powder and asol,

(b) extruding the extrudable mass resulting from step (a),

(c) drying the extrudate resulting from step (b) and,

(d) calcining the dried extrudate resulting from step (c).

Catalyst particles obtained by the above process have an increasedcrushing strength. This is advantageous because such catalysts aretypically applied in a packed bed reactor. Due to the normally highoperating pressure and mass flows in the reactor strong catalystparticles are needed.

The description of the above method will further refer to a silicabinder only. It will be understood that the below preferred conditionswill, when applicable, also apply to other possible binders as heredescribed.

Preferably the silica sol is an acid silica sol. The acid silica sol maybe any colloidal silica having a pH lower than 7. When a pH value ismentioned the pH as measured in water of 18° C. is meant. An example ofa suitable acid silica sol is Nyacol 2034DI (trademark of PQ Corp,Valley Forge, Pa.) or Ultra-Sol 7H (trademark of RESI Inc, Newark). Thesilica powder may be commercially obtained silica powder, for exampleSipernat 22 or 50 (trademark of Degussa AG), Nasilco Ultrasil VN3SP orHiSil 233 EP (trademark of PPG Industries). The solid silica powderparticles preferably have a mean diameter of between 10 μm and 200 μm.

The surface of the acid silica sol particle comprises —OH groups. It isbelieved that for obtaining a catalyst particle having an even higherstrength it is essential that during the mixing of the components instep (a) some or all of these groups are converted to —O— groups. Thisis preferably achieved by adding an amine compound in step (a). It hasfurther been found that when adding an amine compound just beforeperforming step (b) an even more stronger catalyst particle is obtained.It is believed, although we do not wish to be bound to this theory, thatthe stronger catalyst is obtained because not all of the —OH groups onthe sol particle surface are converted into —O— groups. Thus step (a) ispreferably performed by first mixing the zeolite and the acid silica solinto a first homogeneous mixture and subsequently adding the aminecompound to the first homogeneous mixture such that the pH of theresulting second mixture is raised from below 7 to a value of above 8.It can be easily determined by one skilled in the art, bystraightforward experimentation, what the optimal moment in step (a) isfor adding the amine compound. As a guideline it is preferred to add theamine compound during the second half of the time and more preferably inthe last quarter of the time required to mix the components in step (a).Most preferably the amine compound is added within 20 minutes beforeperforming step (b).

The extrudable mass in step (a) should have a sufficient viscosity inorder to be extruded into shapes. One skilled in the art will know howto achieve such a paste like mixture. For example by adding water instep (a) the viscosity can be lowered. The water content of the sol maybe between 60 and 80 wt %. Preferably the water content of theextrudable mass as obtained in step (a) does not exceed 60%, andpreferably is at least 35% by weight.

To obtain an even stronger catalysts it is preferred to maximise theamount of acid silica sol used relative the amount of silica powderused, while still achieving a sufficient viscosity of the extrudablemass. The optimal amount of silica powder to be used will depend on thezeolite content, wherein at a low zeolite content of the catalyst, moresilica powder will have to be used. One skilled in the art can easilydetermine the optimal composition in view of the above teaching.

The amine compound is preferably a compound according to the generalformula R¹R²R³N in which R¹-R³ may be hydrogen and/or an alkyl grouphaving 1-6 carbon atoms. Examples are ammonia, methyl ethyl amine,triethyl amine, of which ammonia, is the most preferred. The aminecompound should preferably be added in such an amount in order to raisethe pH of the mass to alkaline conditions. Preferred conditions are a pHof the mixture obtained in step (a) of above 8. The pH will be lowerthan 14.

Step (a) may for example be performed at ambient conditions by firstmixing the zeolite, optionally the silica powder and acid silica sol,subsequently adding an amine compound and optionally at the end of step(a) a plasticising agent. The plasticiser agent is used to increase theviscosity of the mixture in order to obtain an extrudable mass. Suitableplasticising agents are for example dextrose, gelatine, glucose, glues,gums, salts, waxes, starch and cellulose ethers. Some typical celluloseether binders are methylcellulose, ethylhydroxy ethylcellulose,hydroxybutyl methylcellulose, hydroxymethylcellulose, hydroxypropylmethylcellulose,hydroxyethyl methylcellulose, hydroxybutylcellulose,hydroxyethylcellulose, hydroxypropylcellulose, sodium carboxymethylcellulose, and mixtures thereof. Methylcellulose and/ormethylcellulose derivatives are especially suited as organic binders inthe practice of the present invention with methylcellulose,hydroxypropyl methylcellulose, or combinations of these being preferred.Preferred sources of cellulose ethers are Methocel A4M, F4M, F240, andK75M (Trademarks of Dow Chemical Co).

The extrusion in step (b) may be performed by well known processes asfor example illustrated in Perry's Chemical Engineers' Handbook,McGRAW-HILL International Editions, sixth edition, 1984, p 8-60 to 8-66and in Particle Size Enlargement, Handbook of powder Technology Vol. 1,Elsevier, 1980, p 112-121. Examples of such methods are extrusionperformed by a screw extruder, a plate or ram extruder. The extrudatescan have a wide variety of forms and sizes.

Drying step (c) and calcining step (d) may be performed under conditionswell known to one skilled in the art. Step (c), for example, may takeplace at a temperature of at least 60° C. to about 250° C., for a timesufficient to dry the extrudate, for example, for at least 1 hour.Calcining step (d), for example, may take place in air, or other inertgas, at temperatures ranging from 250° C. to 850° C. for periods of timeranging, for example, from about 1 to about 48 hours or more.

The invention is also related to a catalyst composition having theimproved crushing strength as obtainable by the method as describedabove and its use in hydroconversion processes.

The product obtained in the catalytic dewaxing process according to theinvention may optionally be subjected to a hydrofinishing step.Hydrofinishing is known in the art and examples of suitablehydrofinishing steps are disclosed in, for instance, U.S. Pat. No.5,139,647, WO-A-9201657 and WO-A-9201769. Generally, hydrofinishingcomprises contacting a hydrocarbon feed, in this case a feed comprisingthe dewaxed lubricating base oil, with a hydrogenation catalyst underrelatively mild conditions in order to saturate at least part of thearomatics still present in the dewaxed base oil. Suitable catalysts arethose normally applied for this purpose with noble metal-basedcatalysts, such as those comprising Pt and/or Pd supported on anamorphous silica-alumina carrier or comprising Pt on an alumina support,being preferred options. Hydrofinishing conditions normally involveoperating temperatures up to 350° C. and preferably between 150 and 300°C., operating pressures from 10 to 200 bar and weight hourly spacevelocities of from 0.5 to 7.5 kg/l/h.

The effluent from the catalytic dewaxing process or optionally theeffluent of a hydrofinishing treatment applied subsequently is separatedinto a gaseous fraction and a liquid fraction. Such separation orfractionation can be attained by conventional methods, such as bydistillation under atmospheric or reduced pressure. Of these,distillation under reduced pressure, including vacuum flashing andvacuum distillation, is most suitably applied. The cutpoint(s) of thedistillate fraction(s) is/are selected such that each product distillaterecovered has the desired properties for its envisaged application. Forlubricating base oils, the cutpoint will normally be at least 280° C.and will normally not exceed 400° C., the exact cutpoint beingdetermined by the desired product properties, such as volatility,viscosity, viscosity index and pour point.

The invention will now be illustrated with the following non-limitingexamples.

EXAMPLE 1

A dealuminated, silica bound ZSM-5 catalyst (10% wt dealuminated ZSM-5,90% wt silica binder) was prepared according to the following procedure.ZSM-5 (having a SiO₂/Al₂O₃ molar ratio of 50) was extruded with a silicabinder (10% by weight of ZSM-5, 90% by weight of silica binder). Theextrudates were dried at 120° C. A solution of (NH₄)₂SiF₆ (45 ml of0.077 N solution per gram of ZSM-5 crystallites) was poured onto theextrudates. The mixture was then heated at 100° C. under reflux for 17 hwith gentle stirring above the extrudates. After filtration, theextrudates were washed twice with deionised water, dried for 2 hours at120° C. and then calcined for 2 hours at 480° C. The dealuminated ZSM-5thus obtained had a SiO₂/Al₂O₃ molar ratio 26.0.

The thus obtained extrudate was impregnated with an aqueous solution ofplatinum tetramine hydroxide followed by drying (2 hours at 120° C.) andcalcining (2 hours at 300° C.). The catalyst was activated by reductionof the platinum under a hydrogen rate of 100 1/hr at a temperature of350° C. for 2 hours. The resulting catalyst comprised 0.7% by weight Ptsupported on the dealuminated, silica-bound ZSM-5.

A hydrocracked waxy raffinate having the properties as listed in Table Iwas contacted in the presence of hydrogen with the dealuminated,silica-bound ZSM-5 catalyst at a temperature of 310° C., an outletpressure of 40 bar, a WHSV of 1.0 kg/l.hr and a hydrogen gas rate of 700Nl/kg. Gaseous components were separated from the effluent by vacuumflashing at a cutting temperature of 300° C. The properties of theobtained lubricating base oil product and the yield of the catalyticdewaxing experiment are given in Table II.

TABLE I Properties of hydrocracked waxy raffinate Boiling pointdistribution (% wt) Density 70/4 0.817 Vk40 (cSt) 21.8 IBP-380° C. 10Vk100 (cSt) 4.51 380-420° C. 40 VI 121 420-470° C. 40 Sulphur (ppmw) 2.9470-FBP ° C. 10 Nitrogen (ppmw) <1 Pour point (° C.) +27 IBP (° C.) 334Wax content (% wt) 16.7 FBP (° C.) 538

Vk40 is kinematic vicosity measured at 40° C.; Vk100 is the kinematicviscosity at 100° C.

EXAMPLE 2

Example 1 was repeated except that the content of ZSM-5 was 30 wt %. Theproperties of the obtained lubricating base oil product and the yield ofthe catalytic dewaxing experiment are given in Table II.

EXAMPLE 2a

Example 1 was repeated except that a catalyst was used consisted of 90wt % silica binder, 10 wt % ZSM-12 powder and a platinum loading of 0.7wt %. The crystal size of the ZSM-12 crystallites was 1 μm and theextrudate was dealuminated as in Example 1. The properties of theobtained lubricating base oil product and the yield of the catalyticdewaxing experiment are given in Table II.

EXAMPLE 2b

Example 2a was repeated except that the crystal size was between 0.1 and0.2 μm. See Table II for more results.

EXAMPLE 2c

Example 2b was repeated except that no dealumination treatment was usedto prepare the catalyst. See Table II for more results.

Comparative Experiment A

Example 1 was repeated except that the amount of ZSM-5 crystallites inthe catalyst was increased to 60 wt %. The resulting catalyst comprised0.7% by weight Pt supported on the dealuminated, silica-bound ZSM-5catalyst. The properties of the obtained lubricating base oil productand the yield of the catalytic dewaxing experiment are given in TableII.

TABLE II Product characteristics Example Example Example Example ExampleComp. 1 2 2a 2b 2c Exper. A catalyst ZSM-5 ZSM-5 ZSM-12 ZSM-12 ZSM-12ZSM-5 size = size = size = 1-2 μm 0.1- 0.1- 0.2 μm 0.2 μm no AHSreaction 310° C. 309° C. 358° C. 312° C. 350° C. 294° C. tempera- tureYield 80 78 91 91 82.4 75.6 (% wt) Gas make 4.3 5.5 2.9 3.6 3.6 7.6 (%wt) Pour −16 −16 −16 −16 −16 −16 point (° C.) VI 105 104 108 108 105 101

EXAMPLE 3

Example 1 was repeated except that 10 wt % of SSZ-32 was used instead ofZSM-5 and dealumination was performed as follows: 0.353 grams ofammonium hexafluorosilicate was dissolved in 1420 ml deionised water.Then, this solution passes over 45 grams of extrudates at ambienttemperature for 17 hours. After separation from the solution, theextudates are washed with deionised water, dried for two hours at 150°C. and then calcined for two hours at 480° C. The loading of platinumwas as in Example 1.

The properties of the obtained lubricating base oil product and theyield of the catalytic dewaxing experiment are given in Table III.

Comparative Experiment B

Comparative experiment A was repeated except that 70 wt % of SSZ-32 wasused. Dealumination was performed as follows: 2.68 grams of ammoniumhexafluorosilicate was dissolved in 1562 ml deionised water. Then, thissolution passes over 49.5 grams of extrudates at ambient temperature for17 hours. After separation from the solution, the extrudates are washedwith deionised water, dried for two hours at 150° C. and then calcinedfor two hours at 480° C. The loading of platinum was as in Example 1.

The properties of the obtained lubricating base oil product and theyield of the catalytic dewaxing experiment are given in Table III.

TABLE III Comparative Example 3 Experiment B operating 317° C. 305° C.temperature Yield (% wt) 85.7 79.2 Vk40 (cst) 24.57 27.34 Vk100 (cSt)4.68 4.93 Gas make (% wt) 2.6 7.5 Pour point (° C.) −25 −24 VI 108 104

EXAMPLE 4

Example 2 was repeated at 313° C. starting from a hydrocracked waxyraffinate having the properties as listed in Table IV. The properties ofthe obtained lubricating base oil product and the yield of the catalyticdewaxing experiment are given in Table V.

TABLE IV Properties of hydrocracked waxy raffinate Boiling pointdistribution (% wt) Density 70/4 0.8416 Vk80 (cSt) 14.60 IBP-440° C. 10Vk100 (cSt) 8.709 440-469° C. 30 Vk120 (cSt) 6.021 469-518° C. 40Sulphur (ppmw) 95 518-FBP ° C. 20 Nitrogen (ppmw) 1.1 Pour point (° C.)+41 IBP (° C.) 366 Wax content (% wt) 30 FBP (° C.) 587

EXAMPLE 5

Example 4 was repeated wherein a catalyst was used containing 10 wt % ofTON type zeolite and 90 wt % silica. No dealumination treatment wasapplied. The TON type zeolite crystallites were prepared as describedbelow. The properties of the obtained lubricating base oil product andthe yield of the catalytic dewaxing experiment are given in Table V.

Preparation of the TON type crystallites:

Two mixtures A and B were prepared. Solution A: A solution of 6.66 gAl₂(SO₄)3.18H₂O, 13.65 g KOH (85 wt. %), 4.11 g RbOH (50 wt. %), and32.4 g 1,6-diamino-hexane in 325 g demineralised water was prepared in apolyethylene (PE). container. Solution B: 150 g Ludox AS-40 (Trademarkof DuPont) and 240 g demineralised water were mixed in a PE container.

Solution B was added to solution A while stirring and 0.3 g of ZSM-22seeds were added. After the addition of the seed crystals stirring wascontinued for 10 minutes. The resulting synthesis gel was placed in a 1liter teflon-lined stirred autoclave. The molar composition of the thusprepared synthesis mixture was: 100 SiO₂: Al₂O₃: 27.87 R: 10.67 K₂O: 1.0Rb₂O: 3680 H₂O in which R=1,6-diaminohexane.

The autoclave was closed and the stirrer was adjusted to 600 rpm. Thesynthesis mixture was heated from room temperature to 156° C. within twohours. The synthesis mixture was kept at this temperature for 60 hours.

After synthesis, the zeolite crystals were isolated by filtration andwashed with demineralised water. XRD analysis showed that the productwas excellent crystalline TON without any other crystalline contaminant.The purity was very high; no ZSM-5 and/or cristoballite impurities weredetected.

Comparative Experiment C

Example 5 was repeated except that now a catalyst was used which wasprepared by starting with an extrudate containing 60 wt % TON typezeolite and 40 wt % silica binder. The properties of the obtainedlubricating base oil product and the yield of the catalytic dewaxingexperiment are given in Table V.

TABLE V Comparative Example 4 Example 5 experiment C extrudate 30 wt %ZSM-5 10 wt % TON 60 wt % TON 70 wt % silica 90 wt % silica 40 wt %silica metal 0.7 wt % Pt 0.7 wt % Pt 0.7 wt % Pt loading in finalcatalyst operating 313 340 316 temperature (° C.) Oil yield 86 90 88 (wt%) gas make 5.7 3.7 5.8 (% wt) VI 90 97 94 Pour point −9 −9 −9 (° C.)

The following examples will illustrate the preparation of a catalysthaving a low aluminosilicate zeolite content and a high crushingstrength.

Comparative Experiment D

On a dry basis, 60 weight parts of ZSM-5 (CBV8014 as obtained fromZeolyst International) were intimately admixed with 15 weight parts ofamorphous precipitated silica powder (Sipernat-50 as obtained fromDegussa) and with 25 weight parts of acid colloidal silica (Nyacol2034DI as obtained from PQ Corporation); a homogenous mix was obtainedby mulling. The total moisture content of the mix was adjusted to 55weight percent with deionized water.

5 minutes before extruding the mixture a plasticiser agent, Methocelsource (containing 2.1 wt % methocel), was added to the extrudable massin a ratio of 7/100 of Methocel source relative to the zeolite dry mass.The mixture was extruded to yield cylinder extrudates with a diameter of1.6 mm. The extrudates were subsequently dried at 120° C. for typically2 hours in air and then calcined at 800° C. for 5 hours.

The Flat Plate Crushing Strength was measured by determining the forcein N/cm at which the cylinder extrudate was crushed between two parallelflat plates. The cylinder extrudate was positioned between the plates insuch that the cylindrical axis was parallel with the plates. Thisprocedure was repeated 40 times and the average force at which crushingwas observed was the resulting Flat Plate Crushing Strength (FPCS). Inthis example a FPCS of 60 N/cm was measured. See also Table VI.

EXAMPLE 6

Comparative Experiment D was repeated except that the ZSM-5 content was30 wt %, the silica powder content was 35 wt % and the acid silica solcontent was 35 wt %. A FPCS of 86 N/cm was measured. As a result of thelower ZSM-5 content as compared to Comparative Experiment D one wouldexpect a lower FPCS. The resulting higher FPCS is a result of the highercontent of acid silica sol as compared to Comparative Experiment D. TheFPCS is however not high enough for commercial application. A value ofhigher than 100 N/cm is desirable. See also Table VI.

EXAMPLE 7

Example 6 was repeated except instead of acid silica sol the same amountof basic colloidal silica of the type Ludox HS-30 was used. The FlatPlate Crushing Strength was 80 N/cm.

EXAMPLE 8

Example 6 was repeated except that, after mixing the ZSM-5, silicapowder and acid colloidal silica, ammonia was added. Ammonia as a 2.5 wt% aqueous solution was added in a ratio of 1/12 ammonia solutionrelative to the zeolite dry mass. The resulting pH was 8.8. After addingthe ammonia the mixing was continued for 35 minutes before extruding.The Flat Plate Crushing Strength was 122 N/cm. See also Table VI.

EXAMPLE 9

Example 8 was repeated except that ammonia was added after 35 minutesafter mixing the ZSM-5, silica powder and acid colloidal silica. Afteradding the ammonia the mixing was continued for 10 minutes beforeextruding. The Flat Plate Crushing Strength was 178 N/cm.

TABLE VI acidity ZSM-5 Silica Silica of used content powder sol silicaammonia FPCS Experiment (wt %) (wt %) (wt %) sol added (N/cm) Comp. D 6015 25 acid no 60 Example 6 30 35 35 acid no 86 Example 7 30 35 35 basicno 80 Example 8 30 35 35 acid 35 122 minutes before extru- sion Example9 30 35 35 acid 10 178 minutes before extru- sion

EXAMPLE 10

The catalysts prepared in Example 9 was used in a catalytic dewaxingprocess as described in Example 1. The results in yield and selectivitywere the same as in said Example except that the required temperature toachieve the same reduction in pour point was about 10° C. higher.

EXAMPLE 11

A wax containing feedstock obtained by a Fischer-Tropsch processfollowed by a mild hydroconversion having the properties as listed inTable VII was contacted with a catalyst consisting of 30 wt %dealuminated ZSM-5 70 wt % silica and 0.7 wt % platinum. The carrier wasprepared according to Example 9 and the metal impregnation was performedaccording to Example 1. Contacting took place in the presence ofhydrogen at a temperature of 296° C., an outlet pressure of 50 bar, aWHSV of 1.0 kg/l.hr and a hydrogen gas rate of 750 Nl/kg feed. Gaseouscomponents were separated from the effluent by vacuum flashing at acutting temperature of 390° C. The properties of the obtainedlubricating base oil product and the yield of the catalytic dewaxingexperiment are given in Table VIII.

TABLE VII Boiling range (° C.) Density 70/4 0.784 Vk100 (cSt) 6.244 IBP290 Pour point (° C.) +40 50 vol % 466 FBP 701

TABLE VIII Example 11 operating 296° C. temperature Yield (% wt) 45 Vk40(cSt) 58.62 Vk100 (cSt) 9.75 Gas make (% wt) 12 Pour point (° C.) −30 VI151

EXAMPLE 12

A wax containing feedstock, being the heavy product of a hydrocrackingprocess (hydrowax) which primary products are middle distillates, havingthe properties as listed in Table IX was contacted with a catalyst asused in Example 11 in the presence of hydrogen at a temperature of 330°C., an outlet pressure of 40 bar, a WHSV of 1 kg/l.hr and a hydrogen gasrate of 500 Nl/kg feed. Gaseous components were separated from theeffluent by vacuum flashing at a cutting temperature of 390° C. Theproperties of the obtained lubricating base oil product and the yield ofthe catalytic dewaxing experiment are given in Table X.

TABLE IX Boiling range (° C.) Density 70/4 0.821 Vk100 (cSt) 4.166 IBP202 Pour point (° C.) +36 50 vol % 417 FBP 587

TABLE X Example 12 operating 330 temperature Yield (% wt) 48.1 Vk40(cSt) 58.13 Vk100 (cSt) 7.70 Gas make (% wt) 1.1 Pour point (° C.) −12VI 95

EXAMPLE 13

A feedstock having the properties of a finished base oil as listed inTable XI was contacted with a catalyst as used in Example 11 in thepresence of hydrogen at a temperature of 340° C., an outlet pressure of40 bar, a WHSV of 1 kg/l.hr and a hydrogen gas rate of 500 Nl/kg feed.The properties of the obtained lubricating base oil product and theyield of the catalytic dewaxing experiment are given in Table XII.

TABLE XI Boiling range (° C.) Density 15/4 0.826 Vk100 (cSt) 5.134 IBP353 Pour point (° C.) −19 50 vol % 451 FBP 617

TABLE XII Example 13 operating 340 temperature Yield (% wt) 74.3 Vk40(cSt) 25.98 Vk100 (cSt) 5.214 Gas make (% wt) 17.1 Pour point (° C.) −36VI 136

What is claimed is:
 1. A process for the catalytic dewaxing of a hydrocarbon feed comprising waxy molecules said process comprising: contacting the hydrocarbon feed under catalytic dewaxing conditions with a catalyst composition comprising metallosilicate crystallites, a binder and a hydrogenation component, in which the weight ratio of the metallosilicate crystallities and the binder is between 5:95 and 35:65 and the metallosilicate crystallites have a crystalline microporous structure and are defined as being built up of three-dimensional frameworks of tetrahedral SiO₄ units and tetrahedral M units or tetrahedral SiO₄ units and octahedral M units which units are corner linked via oxygen atoms and wherein M represents Al, Fe, B, Ga or Ti or combinations of these atoms.
 2. The process of claim 1, in which the weight ratio of the metallosilicate crystallites and the binder is between 10:90 and 30:70.
 3. The process of claim 1 in which the binder is a low acidity refractory oxide, which is essentially free of aluminum.
 4. The process of claim 3, in which the binder is silica.
 5. The process of claim 1 in which the metallosilicate crystallites are aluminosilicate zeolite crystallites.
 6. The process of claim 5, in which the aluminosilicate zeolite crystallites is selected from the group consisting of an MFI-type zeolite, a ferrierite group zeolite, a TON-type zeolite, an MTW-type zeolite and an MTT-type zeolite.
 7. The process of claim 5, in which the aluminosilicate zeolite crystallites have been subjected to a dealumination treatment.
 8. The process of claim 7, in which the dealuminated aluminosilicate zeolite crystallites are obtained by contacting the aluminosilicate zeolite crystallites with an aqueous solution of a fluorosilicate salt in which the fluorosilicate salt is representated by the formula: (A)_(2/b)SIF₆ in which ‘A’ is a metallic or non-metallic cation other than H+ having a valence ‘b’.
 9. The process of claim 7, in which an extrudate of the aluminosilicate zeolite crystallites and the binder is contacted with the aqueous solution of the fluorosilicate salt.
 10. The process of claim 1, in which the hydrocarbon feed is a hydrotreated vacuum distillate fraction boiling between 300° and 620° C.
 11. The process of claim 1, in which the hydrogenation component is selected from the group consisting of palladium, platinum, nickel and cobalt in a form selected from the group consisting of sulphidic, oxidic and elemental form.
 12. The process of claim 1, in which the catalyst composition is obtained by the process comprising: (a) preparing an extrudable mass comprising a substantially homogenous mixture of metallosilicate crystallites, water, and a source of the low acidity refractory oxide binder present as a mixture of a powder and a sol; (b) extruding the extrudable mass resulting from step (a); (c) drying the extrudate resulting from step (b); and, (d) calcining the dried extrudate resulting from step (c).
 13. A process for the catalytic dewaxing of a hydrocarbon feed comprising waxy molecules, said process comprising: contacting the hydrocarbon feed under catalytic dewaxing conditions with a catalyst composition comprising metallosilicate crystallites, a binder and a hydrogenation component, in which the weight ratio of the metallosilicate crystallities and the binder is between 5:95 and 35:65, in which the catalyst composition is obtained by the process comprising: (a) preparing an extrudable mass comprising a substantially homogenous mixture of metallosilicate crystallites, water, a source of the low acidity refractory oxide binder present as a mixture of a powder and a sol, (b) extruding the extrudable mass resulting from step (a), (c) drying the extrudate resulting from step (b) and, (d) calcining the dried extrudate resulting from step (c), in which step (a) is performed by first mixing the metallosilicate crystallites, the powder and an acid sol of the low acidity refractory oxide into a first homogeneous mixture and subsequently adding an amine compound to the first homogeneous mixture such that the pH of the resulting second mixture is raised from below 7 to a value of above
 8. 14. The process of claim 13, in which the amine compound is added in step (a) within 20 minutes of performing step (b).
 15. The process of claim 13, in which the amine compound is ammonia.
 16. A catalyst composition comprising: a low acidity refractory oxide binder, which binder is essentially free of aluminum; metallosilicate crystallites; and, a hydrogenation component, wherein the weight ratio of the metallosilicate crystallites and the binder is between 5:95 and 35:65 and the metallosilicate crystallites have a crystalline microporous structure and are defined as being built up of three-dimensional frameworks of tetrahedral SiO₄ units and tetrahedral M units or tetrahedral SiO₄ units and octahedral M units which units are corner linked via oxygen atoms and wherein M represents Al, Fe, B, Ga or Ti or combinations of these atoms.
 17. The catalyst composition of claim 16, in which the weight ratio of the metallosilicate crystallites and the binder is between 10:90 and 30:70.
 18. The catalyst composition of claim 17, in which the binder is silica.
 19. The catalyst of claim 16 wherein the crystallite size is between 0.05 and 0.2 μm and wherein the zeolite crystals have been subjected to a surface dealumination treatment.
 20. The catalyst of claim 19, in which the dealuminated zeolite crystallites are obtained by contacting the zeolite crystallites with an aqueous solution of a fluorosilicate salt, in which the fluorosilicate salt is represented by the formula: (A)_(2/b)SIF_(6,) in which ‘A’ is a metallic or non-metallic cation other than H+ having the valence ‘b’.
 21. The catalyst of claim 20, in which an extrudate of the aluminosilicate zeolite crystallites and the binder is contacted with the aqueous solution of the fluorosilicate salt.
 22. The process of claim 8, where ‘b’ is ammonium. 